Four-Level Interchange | Los Angeles Conservancy
Four-Level Interchange
Photo courtesy Architectural Resources Group

Four-Level Interchange

The Four-Level Interchange at the junction of U.S. Route 101 (the Hollywood Freeway and Santa Ana Freeway) and State Route 110 (the Harbor Freeway and Arroyo Seco Parkway) is a stunning feat of modern engineering, with a style you might not have time to appreciate as you’re negotiating your lane change. Completed in 1949, the junction was the world’s first stack interchange, a multi-tiered structure that separates traffic heading in each direction in dedicated lanes.

The design was an improvement over the more sweeping cloverleaf interchange design for reasons of safety and space—sited as it was in a densely developed area of downtown Los Angeles, there was only so much room for this crucial junction.

The four-level reinforced concrete structure was designed by a team of engineers and built by the James I. Barnes Construction Company. Although it was finished in 1949, it was not put into full use until the freeways it served were completed in 1953. The interchange, sometimes called “The Stack,” was retrofitted after the 1994 Northridge earthquake and renamed the Bill Keene Memorial Interchange after the late local traffic and weather announcer in 2006. It is the only interchange in the region to be certified as a civil engineering landmark by the Society of Civil Engineers, and its robust elegance is a true aesthetic achievement. As the Los Angeles Times said in 1949, “It’s the most photogenic pile of cement in town.”

Photo by Jessica Hodgdon/L.A. Conservancy

Lankershim Depot

Closed for more than thirty years, one of the San Fernando Valley’s oldest buildings gained new life as a coffee shop.
Photo courtesy Architectural Resources Group

Tischler House

At once part of, and thrusting out from, its steep hilliside lot, this late Schindler design is beloved by its original owner and countless observers alike.
Photo by Mitzi March Mogul

Joseph L. Starr Dairy Farmhouse

A private owner brought this rare building back from the brink of demolition, painstakingly restoring it while educating the community about the value of preservation.